Conference endpoint instructing conference bridge to dial phone number

ABSTRACT

Disclosed herein are methods, systems, and devices for improved audio, video, and data conferencing. The present invention provides a conferencing system comprising a plurality of endpoints communicating data including audio data and control data according to a communication protocol. A local conference endpoint may control or be controlled by a remote conference endpoint. Data comprising control signals may be exchanged between the local endpoint and remote endpoint via various communication protocols. In other embodiments, the present invention provides for improved bridge architecture for controlling functions of conference endpoints including controlling functions of the bridge.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.10/032,766 filed Dec. 26, 2001, entitled “System and Method forCoordinating a Conference Using a Dedicated Server,” which claimspriority on U.S. Application No. 60/258,529 filed Dec. 26, 2000 andentitled “System and Method for Coordinating a Conference Using aDedicated Server.”

This application is also a continuation-in-part of U.S. application Ser.No. 10/335,108 filed Dec. 31, 2002, entitled “Method and Apparatus forWideband Conferencing,” which claims priority on U.S. Application No.60/345,929 filed Dec. 31, 2001 and entitled “Method and Apparatus for IPConferencing,” and on U.S. Application No. 60/360,984 filed Mar. 1, 2002and entitled “Systems and Methods for Video Conferencing Across aNetwork.”

This application is also a continuation-in-part of U.S. application Ser.No. 10/378,709 filed Mar. 3, 2003, entitled “System and Method forCommunicating Data during an Audio Conference,” which is acontinuation-in-part of U.S. application Ser. No. 10/335,108, and whichclaims priority on U.S. Application No. 60/360,984.

This application is also a continuation-in-part of U.S. application Ser.No. 10/378,711 filed Mar. 3, 2003, entitled “System and Method forCommunication Channel and Device Control via an Existing Audio Channel,”which is a continuation-in-part of U.S. application Ser. No. 10/335,108,and which claims priority on U.S. Application No. 60/360,984.

This application is also a continuation-in-part of U.S. application Ser.No. 10/897,318 filed Jul. 21, 2004, entitled “A Conference Link betweena Speakerphone and a Video Conference Unit.”

The benefit of priority under 35 U.S.C. § 120 is hereby claimed for theabove-referenced applications. The contents of the above-referencedapplications are hereby incorporated by reference.

This application claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Patent Applications Ser. No. 60/653,657 entitled “Systems,Methods, and Devices for Controlling Functions of a ConferencingDevice,” filed Feb. 15, 2005, which is hereby incorporated by reference.

This application claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Patent Applications Ser. No. 60/______ entitled“Speakerphone Transmitting URL Information to a Remote Device,” havingattorney docket No. 199-0364PUS, filed Mar. 14, 2005, which is herebyincorporated by reference.

This application is related to U.S. application Ser. No. 10/144,561filed May 10, 2002, entitled “Control Unit for MultipointMultimedia/Audio System,” which claims priority on U.S. Application No.60/290,138 filed May 10, 2001 and entitled “Control Unit for MultipointMultimedia/Audio,” which is hereby incorporated by reference.

This application is related to the following applications, all of whichare filed concurrently herewith and whose disclosure is herebyincorporated by reference: U.S. patent application Ser. No. __/______,entitled “Conference Endpoint Controlling Functions of a Remote Device,”having attorney docket No. 199-0363US; U.S. patent application Ser. No.__/______, entitled “Conference Endpoint Controlling Audio Volume of aRemote Device,” having attorney docket No. 199-0428US; U.S. patentapplication Ser. No. __/______, entitled “Conference EndpointInstructing Conference Bridge to Mute Participants,” having attorneydocket No. 199-0430US; U.S. patent application Ser. No. __/______,entitled “Conference Endpoint Instructing a Remote Device to Establish aNew Connection,” having attorney docket No. 199-0431US; U.S. patentapplication Ser. No. __/______, entitled “Conference Endpoint Requestingand Receiving Billing Information from a Conference Bridge,” havingattorney docket No. 199-0432US; U.S. patent application Ser. No.__/______, entitled “Speakerphone Transmitting URL Information to aRemote Device,” having attorney docket No. 199-0364US; U.S. patentapplication Ser. No. __/______, entitled “Speakerphone Using a SecureAudio Connection to Initiate a Second Secure Connection,” havingattorney docket No. 199-0433US; U.S. patent application Ser. No.__/______, entitled “Speakerphone and Conference Bridge which Requestand Perform Polling Operations,” having attorney docket No. 199-0434US;U.S. patent application Ser. No. __/______, entitled “SpeakerphoneTransmitting Password Information to a Remote Device,” having attorneydocket No. 199-0435US; U.S. patent application Ser. No. __/______,entitled “Speakerphone and Conference Bridge which Receive and ProvideParticipant Monitoring Information,” having attorney docket No.199-0436US; U.S. patent application Ser. No. __/______, entitled“Speakerphone Establishing and Using a Second Connection of GraphicsInformation,” having attorney docket No. 199-0437US; U.S. patentapplication Ser. No. __/______, entitled “Conference Bridge WhichDecodes and Responds to Control Information Embedded in AudioInformation,” having attorney docket No. 199-0365US; U.S. patentapplication Ser. No. __/______, entitled “Conference Bridge WhichDetects Control Information Embedded in Audio Information to PrioritizeOperations,” having attorney docket No. 199-0438US; U.S. patentapplication Ser. No. __/______, entitled “Conference Bridge WhichTransfers Control Information Embedded in Audio Information BetweenEndpoints,” having attorney docket No. 199-0439US; and U.S. patentapplication Ser. No. __/______, entitled “Speakerphone TransmittingControl Information Embedded in Audio Information Through a ConferenceBridge,” having attorney docket No. 199-0440US.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of conferencing,and more particularly to systems, methods, and devices for controllingfunctions of an endpoint in an audio conference or a video conferenceand for using a protocol to communicate data during a conference.

2. Description of Related Art

Audio Conferencing and Video Conferencing

Conferencing enables geographically remote individuals or groups tocommunicate with each other from their respective locations.Conferencing serves a valuable purpose by reducing the time and expenserequired by traveling to meet in person. Accordingly, teleconferencingenables increased profitability, productivity, and efficiency within oramong organizations. Conferencing also allows enterprises to speeddecision-making and empower dispersed teams. Conferencing isparticularly beneficial in the fields of business, medicine, education,and government.

In audio conferencing, speakerphones are examples of endpoint devicesused to enable telephonic communication between participants at two ormore sites. An example of a speakerphone is the POLYCOM® SOUNDSTATION®line of products. Video conferencing offers the additional ability tocommunicate graphic information and to view the facial expressions andbody language of the conference participant(s) located at a remote site.Video conferencing offers the benefits of face-to-face communicationwithout the inconvenience, expense, and uncertainty associated withtraveling. An example of a video conferencing unit is the POLYCOM®VIEWSTATION® line of products.

Multimedia Conferencing and Data Conferencing

It is often desirable to send data to, and receive data from, anotherparticipating endpoint during a conference. For example, the data mayinclude slide presentations or other documents related to theconference. In one prior art method, the data may be sent via the audiochannel. However, conventional in-band signaling, such as DTMF(Dual-Tone Multi-Frequency) touchtone signaling, typically suffers fromthe disadvantages that it significantly disrupts a conversation (as thetones must be sufficiently loud to be received reliably), and theachievable data rate is limited.

In another prior art method, the data may be sent via a separatecommunication channel. For example, information may be exchanged amongconference participants via fax, e-mail, or the World Wide Web.Establishing a separate communication channel often requiresparticipants (or their assistants) to call one another to exchangecapabilities, numbers, passwords, etc., and alert meeting participantswhen the connection is established and working. Disadvantageously, thistype of communication can be disruptive and time consuming and can causedelays during the conference. The extra time associated with exchangingdata via a separate channel can increase costs in terms ofcost-per-minute as well as lost productivity.

Conferencing Management

Management of a multipoint conference bridge is required for amultipoint conference. Currently either in-band DTMF signaling orout-of-band Internet connections from a workstation are used. Usingin-band DTMF signaling is both disruptive and limited in itscapabilities. Using an Internet connection from a workstation requiresaccess to a workstation, its connection and knowledge of the address ofthe bridge. Improved methods of managing a conference, includingmonitoring and controlling the various functions, are desirable toprovide greater capabilities without requiring the use of a separateworkstation.

SUMMARY OF THE INVENTION

A need has therefore arisen for a conferencing system that provides forimproved capabilities for exchanging data. The present inventionprovides a conferencing system comprising a plurality of endpointscommunicating data including control data according to a communicationprotocol. A local endpoint may control or be controlled by a remoteendpoint. The endpoints may comprise speakerphones, IP telephones, cellphones, video conferencing units, computers, conference bridges, orother communication devices.

Data comprising control signals may be exchanged between an endpoint anda remote device via various communication protocols. In one embodiment,the protocol may be IP-based. In another embodiment, the protocol may bea modem protocol. In another embodiment, the protocol may be a serialI/O protocol. In another embodiment, the protocol may be according toISDN (Integrated Services Digital Network) standards. In yet anotherembodiment the protocol may be analog. For all of the protocols thecontrol data may be embedded in the audio information using Low ProfileSignaling Protocol (“LPSP”) techniques. For the IP, modem data, andserial I/O protocols, the control data may be provided in a channelseparate from the audio channel. In one embodiment of the presentinvention, a speakerphone is provided which can communicate according toany of the aforementioned protocols.

In other embodiments, the present invention provides for bridgearchitecture for implementing the controlling of endpoint functions. Thebridge comprises an embedded data unit which comprises a control unit.In some embodiments, the bridge detects the presence of embedded controldata and decodes the data. In other embodiments, the bridge detects thepresence of embedded control data but does not decode it.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts an exemplary block diagram of a conferencing system inaccordance with one embodiment of the present invention.

FIG. 1B depicts another exemplary block diagram of a conferencing systemin accordance with one embodiment of the present invention.

FIG. 2 depicts an exemplary block diagram of a multipoint conferencingsystem in accordance with one embodiment of the present invention.

FIG. 3 depicts an exemplary block diagram of a conferencing system inaccordance with one embodiment of the present invention wherein anIP-based communication protocol is utilized.

FIG. 4 depicts an exemplary block diagram of a conferencing system inaccordance with another embodiment of the present invention wherein amodem communication protocol is utilized.

FIGS. 5A and 5B depict an exemplary block diagram of a conferencingsystem in accordance with another embodiment of the present inventionwherein a serial I/O protocol is utilized.

FIGS. 6A, 6B, and 6C depict an exemplary block diagram of a conferencingsystem in accordance with yet another embodiment of the presentinvention wherein a LPSP communication protocol is utilized.

FIG. 7 depicts an exemplary block diagram of a conferencing system inaccordance with one embodiment of the present invention wherein a LPSPcommunication protocol employing a spread spectrum technique isutilized.

FIG. 8 depicts an exemplary audio signal in accordance with theembodiment of FIG. 7.

FIG. 9 depicts an exemplary carrier signal in accordance with theembodiment of FIG. 7.

FIG. 10 depicts an exemplary product signal in accordance with theembodiment of FIG. 7.

FIGS. 11A and 11B depict an exemplary block diagram of a conferencingsystem in accordance with one embodiment of the present inventionwherein a LPSP communication protocol employing a notch filter isutilized.

FIG. 12 depicts an exemplary audio signal frequency spectrum inaccordance with the embodiment of FIGS. 11A and 11B.

FIG. 13 depicts an exemplary audio signal frequency spectrum afterfiltering in accordance with the embodiment of FIGS. 11A and 11B.

FIG. 14 depicts an exemplary modulated carrier signal in accordance withthe embodiment of FIGS. 11A and 11B.

FIG. 15 depicts an exemplary product signal in accordance with theembodiment of FIGS. 11A and 11B.

FIGS. 16 and 17 depict an exemplary block diagram of a conferencingsystem comprising a bridge in accordance with one embodiment of thepresent invention.

FIG. 18 depicts an exemplary block diagram of a speakerphone inaccordance with one embodiment of the present invention whereincapability for a variety of communication protocols is provided.

FIG. 19 depicts an exemplary flow diagram of processing HSSB (High SpeedSer. Bus) data packets.

DETAILED DESCRIPTION OF THE INVENTION

As shown in the exemplary drawings wherein like reference numeralsindicate like or corresponding elements among the figures, an embodimentof a system according to the present invention will now be described indetail.

I. Endpoint Controlling or Controlled by a Remote Device

Reference is now made to FIG. 1A, which depicts an exemplary blockdiagram of a conferencing system 10 in accordance with the principles ofthe present invention. The system comprises a plurality of conferenceendpoints 12 and 14. Each of the endpoints 12 and 14 can call and becalled. Each of the endpoints 12 and 14 generates and/or terminatesinformation streams. Each of the endpoints 12 and 14 comprises a controlmodule. In accordance with the present invention, a local endpoint cancontrol one or more functions of a remote endpoint by using controlsignals according to a certain protocol. Conversely, one or morefunctions of the local endpoint can be controlled by the remote endpointby using control signals according to a certain protocol.

One or more of the endpoints 12 and 14 may comprise a speakerphone foruse in an audio conference. A speakerphone is a telephone that includesat least a loudspeaker, a microphone, and one or more microprocessors.In the preferred embodiments the speakerphone allows full duplexoperation and may include wide band operation. A speakerphone may alsohave various connections to another speakerphone. The connection may bevia an analog Plain Old Telephone System (“POTS”) line, a digitalservice line such as an Integrated Services Digital Network (“ISDN”)line, or an Internet Protocol (“IP”) connection, for example.

In addition, one or more of the endpoints 12 and 14 may comprise an IPtelephone (sometimes referred to as “IP phone”). IP telephony refers tocommunications via an IP-based network such as the Internet or anintranet rather than the PSTN. An IP phone is a telephone that iscapable of transporting voice over a network using IP-based data packetsinstead of circuit-switched connections over voice-only networks. Intransmitting an IP call, the IP phone converts an analog signal todigital format and compresses/translates the signal into IP packets fortransmission over the IP network. In receiving an IP call, the IP phonedecompresses/translates a digital signal and converts the signal toanalog format.

One or more of the endpoints 12 and 14 may comprise an analog phone 13coupled to an adapter unit 15, as shown in FIG. 1B. The adapter unit 15is connected in series with the analog phone 13. The adapter unit 15 maybe connected to the network 16 via POTS connection, or an IP connection,or a modem connection, etc. In accordance with certain embodiments ofthe present invention, the adapter unit 15 enables the endpoint 12 toembed a control signal in an outgoing audio signal, according to a lowprofile signaling protocol, as discussed further herein. The adapterunit 15 can also extract and decode a control signal from an incomingaudio signal according to a low profile signaling protocol.

One or more of the endpoints 12 and 14 may also comprise a videoconferencing unit (“VCU”). A VCU transmits, receives, and processesvideo images as well as audio signals. A VCU typically comprises a videoprocessing component and an audio processing component. The videoprocessing component may include a camera to capture live images ofconference participants, and a video display for showing real-time videoimages of conference participants or images of documents. The audioprocessing component of a video conferencing unit may include one ormore microphones and one or more loudspeakers. In one embodiment, forexample, the endpoint 12 and/or the endpoint 14 of FIG. 1A may beembodied as the VCU depicted in FIG. 3 or may include an ISDN interfacein place of the IP interface.

One or more of the endpoints 12 and 14 may also comprise a conferencebridge. A bridge provides the capability for a multipoint conference(i.e., a conference among three or more sites), but can also be used fora point-to-point conference (i.e., a conference between two sites). Abridge may also be referred to as an MCU (multipoint conferencing unitor multi control unit).

FIG. 2 depicts a multipoint conferencing system 20, comprising a bridge22 connected to multiple endpoints 24, 25, and 26 via networks 27, 28,and 29. The endpoints 24, 25, and 26 may communicate at different datarates and according to different coding standards. The bridge 22facilitates transcoding and processing of signals received from theendpoints 24, 25, and 26. The bridge 22 also performs summing, mixing,and other processing of signals, and sends signals to the endpoints 24,25, and 26.

Additional types of endpoint devices may be utilized with the presentinvention. For example, any communication device, whether a cell phone;PDA; computer with microphone, speaker, and appropriate software;cordless phone; answering machine; or room conferencing system, etc. maybe used as an endpoint device. The foregoing are illustrative examplesof endpoint devices and are not intended to be exhaustive. It will beappreciated by one skilled in the art that additional types ofcommunication devices are within the scope of the present invention. Inaddition, the endpoint devices may include various components. It shouldbe noted that not all elements of the endpoints discussed herein arenecessary in alternative embodiments. Likewise, additional elements maybe included in alternative embodiments. In addition, additional devicesmay be coupled to or integrated with an endpoint, such as displayscreens, overhead projectors, cameras, printers, scanners, microphones,loudspeakers, computers, etc.

The endpoints 12 and 14 communicate via a network 16. Audio signals maybe transmitted and received via the network 16. Video signals may alsobe transmitted and received via the network 16. Furthermore, data,including but not limited to, control signals, may be transmitted andreceived via network 16. In some embodiments, the network 16 may be thePSTN. In other embodiments, the network may be an IP-based network.Various communication protocols may be used for exchanging signals anddata, including but not limited to control signals, between the endpoint12 and the endpoint 14.

With reference to FIG. 2, control data may be sent from any endpoint 24,25, or 26 to control another endpoint including the bridge 22. Inaddition, control data is bi-directional, and each endpoint 24, 25, and26 including the bridge 22 can send and transmit control data. Forinstance, control data may be sent from the bridge 22 to control one ormore of the endpoints 24, 25, and 26. Thus, control signals may be usedto control or be controlled by another endpoint including the bridge 22.

In order to send digital data in addition to the normal audio or videosignals over the existing audio or video channel, a data connection maybe embedded within an existing audio or video connection. Utilizing thisprocess to transmit data during audio or video conferencing, varioustypes of data aside from the normal audio or video data can be exchangedby way of embedded digital signals.

For example, a participant in a multipoint call, using a multipointbridge, may wish to manage and supervise that call. The participant canuse the existing audio connection to carry additional supervisoryinformation, allowing her to monitor and control the bridge operationfor information such as number and identification of participants,current cost of conference, session identification, number of channelssimultaneously enabled, and many other functions associated with bridgecontrol. This channel also gives the supervisor, over the establishedchannel, the ability to send data to the bridge, performing operationssuch as muting some or all other endpoints, disconnecting some or allother users, transferring supervisor status to another user, changingoperating mode of the bridge, initiating a polling process, and numerousother functions. Additional various examples of control functions willbe discussed below.

For example, control data may include instructions to adjust a farendpoint's volume. For example, a participant at one site (listeningparticipant) may detect that another participant (speaking participant)is sending audio at an unusually low amplitude. Rather than interruptingthe speaking participant and asking that he speak more loudly or closerto the microphone, or rather than increasing the listening participant'svolume, the listening participant can send a command message from hisendpoint through the existing audio channel to control the far endpointby increasing its transmit gain to compensate.

As another example, the control signals may include instructions for thebridge to dial a specific phone number or connect to a specific IPaddress. In this manner, a conferee may be added to a conference call.Advantageously, by having the bridge call a participant instead ofhaving the participant call the bridge, the participant need notremember any phone numbers, conference ID numbers, or passwords to joina conference.

As another example, the control signals may include instructions to mutesome or all other endpoints. For example, in an audio conference amongone hundred participants, one may be granted speaker status by thebridge, and all others can be automatically muted. The conference canthen proceed in half-duplex mode rather than full-duplex mode.Advantageously, less bandwidth is required for half-duplex mode. Inaddition, when one participant is the primary speaker for a length oftime, automatically muting all other participants' endpoints greatlysimplifies the process of mixing and processing all of the endpointaudio signals. Furthermore, the other ninety-nine participants need notremember to mute their endpoints manually. This also advantageouslyavoids the possibility of some of the other ninety-nine participants'fumbling with their endpoint devices to find a mute button andaccidentally hanging up.

A process may also be provided to selectively allow the mutedparticipants to contribute to the conference. For example, anotherparticipant can ask a question by pressing a question button on hisendpoint. His endpoint can send a message to the bridge indicating“Question requested.” The bridge decodes the message, and sends amessage to the speaker's endpoint indicating a question has beenrequested (e.g., “Question requested by User 71”).

The speaker presses an “Accept question” button on her endpoint. Amessage is sent to the bridge, indicating that the question has beenaccepted. The bridge decodes this message, and forwards a message to thequestioner (User 71). The questioner's endpoint decodes the message anddisplays “Please ask question now” on its LCD. The questioner's endpointis unmuted, and the participants can hear his question.

In addition, the control signals may provide instructions that a farendpoint establish a new connection, such as an IP connection to awebsite.

In audio conferences, it is often desired to add additional content tothe audio conference. This may be by adding a graphics connection toshare a slide presentation, or by sending photographs, by adding a videoconnection, or by some other mode. This can be done by a variety ofmeans, but most often involves a considerable degree of effort anddelay, and results in considerable disruption of the meeting. Thegreatest part of this disruption is due, not to the actual exchange ofthe additional information, but to the effort required to establish theconnection by which the additional material will be sent. This effortwill often entail the comparison of additional telephone or fax numbers,IP addresses, passwords, session identification numbers, and a tediousrepetition of same while all participants compare status information tofigure out why the connection is not occurring.

For example, in an audio conference between two participants, oneparticipant may have a slide presentation he wishes to show to the otherparticipant from his computer. Participant A (PA) connects hiscomputer's video port to a special port on his speakerphone. Thespeakerphone is designed such that it recognizes the presence of videoat this special port, or on command as by a press of a button, as aninstruction to establish an IP connection to the far end, and to thencompress and send whatever video it sees at this special port. The videois sent over the IP connection, either as a separate channel on theexisting IP connection or as a second communication link.

PA's speakerphone constructs the message “Meet me atwww.polycom-calypso.com, using session identification ABCDEFGHIJ andpassword 12345678.” PA's speakerphone encodes this message and embeds itin the ongoing audio signal.

Participant B's (PB) speakerphone, which has a complementary capability,detects this message and follows its instructions. PB's speakerphoneuses an IP connection, either an additional channel or a second link,and goes to the stated website, enters the stated data, and beginsreceiving data which it recognizes as compressed video which it canreconstruct. PB's speakerphone reconstructs this received data, anddisplays it to PB using a connected display from this point through therest of the meeting.

In the situation where each speakerphone is connected to avideoconferencing unit, such as by an HSSB link described below, the newconnection can be a video link between the two videoconferencing units.Speakerphone A is linked to videoconferencing unit A and speakerphone Bis linked to videoconferencing unit B. Participant A elects to migratethe conference between Participants A and B from audio only to video andaudio. Participant A selects this function on speakerphone A.Speakerphone A retrieves the telephone number or IP address, or both,from videoconferencing unit A. This information is then transmitted tospeakerphone B in a message that says “Have your video unit call mine at123-456-7890.” Speakerphone B receives the message and provides therequest and number or numbers to videoconferencing unit B.Videoconferencing unit B then initiates the videoconference to completethe connection. This is an example of commands being transferred amongvarious units in a chain to perform the desired operation.

Furthermore, the control signals may include instructions for a bridgeto send billing information to one of the endpoints. Advantageously, anendpoint can request real-time billing reports and detailed recordswhich may include various parameters in order to facilitate rapidendpoint billing.

In addition, a participant can receive cost-of-conference-so-far statusinformation. For example, in an audio conference among severalparticipants, one may wish to monitor the cumulative cost of theconference. The participants call into an agreed-upon audio bridge. Onepresses a “Supervisor” button on her telephone, followed by a password,PIN number, or other security information. The supervisor's endpointassembles and sends a message containing the information “I am thesupervisor, and this is my password.” The bridge detects and decodesthis message. The bridge now understands that this particular connectionis the supervisor. The bridge begins sending messages to the supervisor,for example, periodically (e.g., every minute) or whenever a participantjoins or leaves the conference, with the format “Cost so far $51.80.”The supervisor's endpoint decodes these messages from the bridge, anddisplays the information on her endpoint's display.

An advantage of this technique lies in the fact that data is availablecontinuously or for significant durations during a session, as opposedto momentary data packets such as DTMF messages. This makes possiblecontinuous monitoring of call status, which enables such functions askeeping track of cumulative cost of a call.

In addition, an endpoint can provide payment information to the bridge.For example, an endpoint may provide a participant's credit card numberor other payment instructions. Other payment methods may be used suchas, for example, billing the call to each participant via hiscommunication service provider, or using a credit account or pre-paidaccount of the participant at the conference service provider, etc.

The foregoing are illustrative examples of control functions wherein anendpoint including a bridge may control or be controlled by anotherendpoint including a bridge. The foregoing examples are illustrativeonly and are not intended to be exhaustive. It will be appreciated byone skilled in the art that additional types of control functions arewithin the scope of the present invention.

In one embodiment of the present invention, the network 16 of FIG. 1A(and/or any of the networks 27, 28, and 29 of FIG. 2) may be an IP-basednetwork. The network may comprise a packet switched IP-based networksuch as a local area network (LAN) utilizing, for example, Ethernettechnology, or a wide area network (WAN) such as the Internet. Devicescommunicating through an IP-based network employ an appropriatecommunication standard and an appropriate protocol such as TransmissionControl Protocol/Internet Protocol (TCP/IP).

Any IP-based standard may be employed, whether now known or laterdeveloped. Examples of presently known IP-based standards includewithout limitation Real Time Transport Protocol (RTP), Real TimeStreaming Protocol (RTSP), Session Initiation Protocol (SIP), H-Series(e.g., H.263, H.323, and H.324, etc.), T-Series (e.g., T.120, etc.), andG-Series (e.g., G.711 and G.722, etc.), among others.

Reference is now made to FIG. 3, which depicts an exemplary conferencingsystem 100 employing an IP-based protocol in accordance with oneembodiment of the present invention. One or more of the endpoints 12 and14 of FIG. 1A or one or more of the endpoints 24, 25, and 26 of FIG. 2may be embodied as the endpoint 102 shown in FIG. 3. Although theendpoint 102 is depicted and described as a video conferencing unit, itwill be appreciated by those of skill in the art that the videocapability is optional, and the endpoint 102 may alternatively be adevice for audio conferencing without video conferencing capability.

The endpoint 102 receives input from and transmits output to a varietyof peripheral devices, and additionally communicates with other devices,including one or more remote conference endpoints 101, via private orpublic IP networks. The endpoint 102 acquires video and audioinformation (typically representative of the images and voice of thenear conferencing participants) respectively generated by one or morecameras 104 and one or more microphones 106. The endpoint 102 processesthe acquired video and audio information, and transmits the processedinformation to the one or more remote conference endpoints 101 connectedto the endpoint 102 via an IP link 108.

The endpoint 102 receives video and audio information (typicallyrepresentative of the images and speech of the remote conferenceparticipants) from the remote conference endpoint. The received videoand audio information is processed by the endpoint 102 and the processedvideo and audio information is directed to a video monitor 110 andspeakers 112 so as to present to the near conference participants theimages and speech of the remote conference participants. The endpoint102 may also receive input from or direct output to other peripheraldevices, such as a videocassette player/recorder, document camera or LCDprojector.

The endpoint 102 comprises various components interconnected forcommunication by at least one bus 114. The components may comprise acentral processing unit (CPU) 116. The CPU 116 interprets and executesprogram instructions loaded from a memory 124. The memory 124, which mayvariously include volatile RAM, non-volatile ROM, and/or storage devicessuch as magnetic disk drives or CD-ROMS, stores executable programs,data files, and other information.

The components may further comprise an audio input/output interface 118coupled to one or more microphones 106 and one or more speakers 112. Theaudio input/output interface 118 performs analog-to-digital anddigital-to-analog conversion and performs other signal processing tasksin connection with audio information received from one or moremicrophones 106 or sent to one or more speakers 112. The one or moremicrophones 106 may be internal to the endpoint 102, or external to theendpoint 102, or a combination. Likewise, the one or more speakers 112may be internal to the endpoint 102, or external to the endpoint 102, ora combination.

The components may optionally comprise a video input/output interface120 coupled to one or more cameras 104 and one or more monitors 110. Thevideo input/output interface converts and processes video informationreceived from one or more cameras 104 and sent to one or more videomonitors 110. The one or more cameras 104 may be internal to theendpoint 102, or external to the endpoint 102, or a combination.Likewise, the one or more monitors 110 may be internal to the endpoint102, or external to the endpoint 102, or a combination.

An IP network interface 126 enables connection of the endpoint 102 to anIP network 130. The IP interface 126 relays signals to and from aprotocol stack 122. The protocol stack 122 establishes Internet voiceand protocol video conferencing sessions. Data received from the IPnetwork 130 is passed to a control module 124. The control module 124detects whether control data is embedded in the audio or video. Thecontrol module 124 may decode the control data, or alternatively forwardthe control data without decoding it.

In accordance with the present invention, the control module 124 enablesusers to manage calls and control functions of the remote endpoint(s)101. Furthermore, the endpoint 102 may be controlled by the remoteendpoint 101. Supervisory control of conferencing is also handled by thecontrol module 124, which provides control data to conferencing partiesin order to modify conferencing parameters. These parameters may includedirecting the type and manner of audio and/or video display, callerintervention, secure access and retrieval of data, and a variety ofother functions. The endpoint 102 may provide a digital control channeland a voice channel over the same link to the IP network 130. On areceiving end, the control data may be sent to a control module of thereceiving endpoint 101 where the parameters may then be altered.

Thus, in accordance with the present invention, functions of theendpoint 102 can be controlled by one or more of the endpoints 101.Furthermore, the endpoint 102 can control functions of one or more ofthe endpoints 101. Control signals may be sent between the endpoint 102and the one or more endpoints 101 via the same communication channel asthe audio (and video) signals. As described above, control signals mayalso be used to control or be controlled by a bridge.

In addition, user controls interface 132 enables entry of user inputfrom a local conference participant by receiving and processing signalsreceived from user controls 134. User controls 134 may include awireless remote control device having a set of keys engageable by theuser. The keys may include, for example, numeric keys, directionalarrows, volume and camera position adjustment keys, a menu key, and aslideshow key for initiating transmission of slideshow images to theremote conference endpoint 101. Engagement of keys causes acorresponding infrared or radio frequency code to be sent to usercontrols interface 132. User controls interface 132 is thus operative toreceive and interpret the codes for further processing by othercomponents of the endpoint 102. Entry of user input, such as telephonenumbers or configuration information, may be advantageously accomplishedthrough use of a graphical user interface (GUI), displayed on the one ormore monitors 110, which prompts the user for specified information.

In another embodiment, communications may be exchanged according to amodem data protocol. For example, a V.xx standard, H.324 standard, or aBell 212 protocol may be utilized. The V Series are ITU (InternationalTelecommunication Union) standards for data communication over thetelephone network. Prior to the ITU standards, the American Telephoneand Telegraph Company and the Bell System offered its own standards(e.g., Bell 103 and Bell 212A). V.22 is an ITU standard for 1200 bps(bits per second) duplex modem standardized for use in the generalswitched telephone network and on point-to-point 2-wire leasedtelephone-type circuits. V.22bis is an ITU standard for 2400 bits persecond duplex modem using the frequency division technique standardizedfor use on the general switched telephone network and on point-to-point2-wire leased telephone-type circuits. V.32 is an ITU standard for afamily of 2-wire, duplex modems operating at data signaling rates of upto 9600 bps for use on the general switched telephone network and onleased telephone-type circuits. V.32bis is an ITU standard for a duplexmodem operating at data signaling rates of up to 14,400 bps (bits persecond) for use on the general switched telephone network and on leasedpoint-to-point 2-wire telephone-type circuits. V.34 is an ITU standardprotocol for modems operating at data signaling rates of up to 33,600bps for use on the general switched telephone network and on leasedpoint-to-point 2-wire telephone-type circuits. V.61 is an ITU standardfor a simultaneous voice plus data modem, operating at a voice plus datasignaling rate of 4800 bps, with optional automatic switching todata-only signaling rates of up to 14 400 bps, for use on the generalswitched telephone network and on leased point-to-point 2-wire telephonetype circuits. V.70 is an ITU standard for the simultaneous transmissionof data and digitally encoded voice signals over the GSTN, or over2-wire leased point-to-point telephone type circuits. V.90 is an ITUstandard for a digital modem and analog modem pair for use on the PSTNat data signaling rates of up to 56,000 bps downstream and up to 33,600bps upstream. V.xx modems automatically adjust their transmission speedsbased on the quality of the lines. H.324 is an ITU standard for for lowbit-rate multimedia communication terminals using V.34 modems and V.8procedures to start or stop data transmission over the GSTNs. H.324provides capabilities to commence a voice call and add a video channel.Additionally, H.324 provides for an optional data channel. Theseadditional channels are developed using protocols according to H.324.Thus H.324 is an example of modem transferring audio and data overseparate channels. Additional information regarding ITU standards can befound at the ITU's website at http://www.itu.int.

An exemplary audio conferencing system employing a modem data protocolbased protocol in accordance with one embodiment of the presentinvention is shown in FIG. 4. The system comprises at least twoendpoints 200 and 201 communicating via a network 203 such as the PSTNpursuant to a modem data protocol.

An audio input/output interface 202 can receive audio data from a sourcesuch as one or more microphones 201. The audio input/output interface202 can also perform audio data output functions, such as forwardingaudio signals to one or more speakers 201.

Audio from at least one microphone is forwarded to a codec 204 via audioinput/output component 202 for compression of the audio data.Preferably, the codec 204 can be operated at different bandwidths aswell as at different data rates. In other words, the codec 204 is acodec designed such that for a constant level of quality, a requireddata rate will be reduced as the bandwidth is reduced. In order tocreate the codec 204, for example, a constant algorithm can be employedwith the coding parameters of the algorithm adjusted to achieve thereduction in bandwidth according to the reduction in data rate.Alternatively, various codecs 204 may be selected depending upon thedata rate available, a fixed narrow bandwidth codec 204 can be combinedwith a variable bandwidth codec 204, etc. However, any codec 204 iswithin the scope of the invention.

The compressed audio data may be forwarded to a modem 206. The modem 206converts the audio data into an analog signal for transmission via aPOTS audio connection 214, or a cable audio connection 214, etc. Themodem 206 can establish the frequency at which the data will betransmitted via the audio connection 214. The modem 206 forwards theaudio signals to a POTS interface 212, which sends the audio signals tothe one or more remote endpoints 201 via the audio connection 214.

A channel adaptor 208 may convert the digital data into a formatacceptable for transmission via a data channel. However, the compressedaudio data forwarded to the channel adaptor 208 is not converted into ananalog signal. Rather, the audio data forwarded to the channel adaptor208 is transmitted in digital form via a digital transmission medium.

In accordance with one embodiment of the present invention, a controlmodule 210 is provided to enable users to manage calls and controlconference functions. Supervisory control of conferencing is handled bythe control module 210, which provides control data to conferencingparties in order to modify conferencing parameters. These parameters mayinclude directing the type and manner of audio and/or video display,caller intervention, secure access and retrieval of data, and a varietyof other functions. The modem 206 receives both the audio and controldata signals, and forwards the signals to the line interface 214 fortransmission over the PSTN 203. Thus, the endpoint 200 may provide adigital control channel and a voice channel over a modem link to thePSTN 203. On a receiving end, the control data may be sent to a controlmodule of the receiving communications device where the parameters maythen be altered.

In accordance with certain embodiments of the present invention, aserial I/O protocol may be used such as USB (Universal Ser. Bus) orIEEE1394, etc. In addition, a High-Speed Ser. Bus (“HSSB”) or otherproprietary link may be used to implement a conference link between oramong conference devices, such as a video conferencing unit, aspeakerphone, a microphone pod, or a loudspeaker, for example. Theconference devices may be located in the same conference room. WithHSSB, all data in a conference may be transmitted among linked devices.With HSSB, data and processing power become commodities within thesystem and can be shared among the linked devices. Adding new devices,such as a speakerphone or a video conference device, can add newcapacity to the whole linked system, not just within the new device. Thecapability of the system can be increased incrementally. With HSSB, mostfunctions may be advantageously distributed and reallocated to anydesired device. The control of any devices within the linked system canbe shared among the linked devices, i.e., from one of the linkeddevices, one may control the operation of all devices within the linkedsystem.

An exemplary conferencing system utilizing a HSSB-based protocol inaccordance with one embodiment of the present invention is shown inFIGS. 5A and 5B. FIG. 5A depicts a block diagram of an exemplary videoconference unit 400, and FIG. 5B depicts a block diagram of an exemplaryspeakerphone 500 that is linked to the video conference unit 400.

The video conference unit 400 comprises a central module 440, which mayinclude loudspeakers 422 and 424, a connection to a camera 412, and aconnection to a display screen 410. The central module 440 may comprisehardware, software, firmware, and any combination thereof. The centralmodule 440 may include various interfaces for additional video and audiocomponents: video input interface 441, video output interface 442, audioinput interface 445, and audio output interface 446. Each interface hasconnections to multiple audio or video channels.

The signal processing and control is performed by a processor unit 450,which is coupled to various audio/video components or interfaces throughintermediates 451, 452, 453, and 454. Those intermediates 451-454perform signal conversions, such as digital-to-analog conversions andanalog-to-digital conversions, etc. While they are shown as separateblocks, they could be integrated into a single module or an integratedchip. The processor unit 450 is supported by a memory module 456(typically RAM) and a mass storage 457 (typically flash memory). Signalprocessing programs may be stored in the mass storage 457. Componentprofiles, which may be used in certain situations, can be stored thereas well.

The central module 440 may comprise a number of different networkinterfaces, such as an interface 443 for a digital network, an HSSBinterface 449 which will be described in more detail below, and aninterface 444 for an analog network, typically for connecting with POTSlines. The interface 444 may comprise a POTS line for each audio channelwhen a stereo conference is used. The digital interface 443 may supportvarious digital connections, such as ISDN, Ethernet, or USB, etc. TheISDN connection may be used for a video conference connection through anISDN network. The Ethernet or LAN connection may be used for videoconferencing through the Internet or over a LAN. The USB connection maybe used to exchange an additional audio/video media stream, such asadditional cameras, microphones, computers with additional documents,etc.

A remote control interface 448 may further be provided. The remotecontrol interface 448 can receive control commands from a handheldremote control (not shown) and transmit the commands to the centralmodule 440 to control the operation of the video conference unit 400.The HSSB interface 449 is a special interface for a conference link,according to an embodiment of the present invention. The HSSB interface449 uses the HSSB protocol for transmitting/receiving audio data andcontrol data.

A block diagram of a speakerphone 500 according to an embodiment of thepresent invention is shown in FIG. 5B. The speakerphone 500 may comprisea central module 540, including microphones 532 and 534, loudspeakers522 and 524, signal converters 551 and 553, audio input interface 545,audio output interface 546, an HSSB interface 549, a digital networkinterface 543, an analog network interface 544, a memory module 556, amass storage module 557, and a processor 550. The central module 540 maycomprise hardware, software, firmware, and any combination thereof.

According to an embodiment of the current invention, the videoconferencing unit 400 is connected to speakerphone 500 through aconference link 360. The conference link 360 connects the videoconference unit 400 and the speakerphone 500 through the HSSB interfaces449 and 549, respectively. The link 360 can be implemented and used invarious different ways.

Analog Link

In one implementation, the link 360 is an analog audio link whichconnects analog microphone signals and loudspeaker signals between thevideo conferencing unit 400 and the speakerphone 400. With this link360, the microphones in the speakerphone 500 pick up sounds (e.g.,voices) from conference participants and supply such microphone signalsto the video conferencing unit 400 for further processing. At the sametime, the loudspeakers in the speakerphone 500 reproduce voices from thefar end. This way, the external microphones and loudspeakers for thevideo conference unit 400 may be eliminated from the conference room.The audio processing then can be performed by the audio processor in thespeakerphone 500. The audio processing of the speakerphone 500 may havevarious audio features such as full-duplex audio, noise reduction,acoustic echo cancellation, and even stereo audio pickup andreproduction. In this embodiment, the link 360 between the videoconference unit 400 and the speakerphone 500 can be, for example, athree-wire cable, as used in cell phone headsets or stereo earphones.The three-wire cable includes a wire for a loudspeaker signal, a wirefor a microphone signal, and a wire for common ground.

Digital Link

Alternatively, the link 360 may be a digital link between the videoconference unit 400 and the speakerphone 500. The digital link may bereferred to a HSSB or a Conference Link. In this embodiment, a digitalcable 360 couples the video conference unit 400 and the speakerphone 500through the HSSB interfaces 449 and 549, respectively.

When a digital connection is used, various data packets can betransmitted between the video unit 400 and the speakerphone 500. Thesedata may include multiple channels of digitized audio data between thetwo units, as well as control data.

Physical Layer of HSSB

According to one embodiment of the present invention, the digital link360 couples the video conference unit 400 and the speakerphone 500through the HSSB interfaces 449 and 549, respectively. There are twodedicated bi-directional buses in the HSSB: a data bus and a clock bus.The HSSB interface may send or receive in either direction. The physicallayer of the link 360 preferably uses LVDS (Low Voltage DifferentialSignaling). LVDS is one of the many signaling standards capable ofsupporting high speed communication at low power consumption. In oneembodiment, the HSSB is physically similar to an Ethernet connection,using Category 5 type of cable for the connection, i.e., a cable withunshielded four pairs of twisted copper wires. But the HSSB interfaceuses its own link protocol for transmitting data.

At power on, each device detects the presence of a clock on one of thedevice link connections. This enables the device to determine which portis “upstream” or “downstream” and also determines which port requires aclock drive. Since the power for the linked devices is supplied by thelink 360, periodic determination of the downstream port is not required.In the case of linked devices that do not have an independent clocksource on board, the logic can be driven by the link clock after thesource is determined. Source determination can be accomplished by havingtwo counters that are reset during power on and are clocked by theirrespective ports. Once a counter has reached a certain count, therespective port is declared as the clock source. The other counter isdisabled. The rest of the logic is brought out of reset, and the clocksource is supplied to the rest of the logic. Which counter reaches therequired count is also used to determine which device is the upstreamdevice or the downstream device. Other methods may also be used todetermine the clock source, for example, based on the device IDs, or bythe time when the conference software or HSSB software is installed. Theclock source may determine the master/slave devices. The master istypically the one that provides clock data.

In one implementation, the total data rate is 36.768 Mbps, divided intoframes of 32 kHz or 48 kHz. These can be partitioned, for example, toprovide 46 audio channels (16-bit audio at 48 ksps for >20 kHzbandwidth) in an audio-only system, all two-megabit H.263 or H.264 videochannels, 36 Mbps of raw high-availability data bandwidth, or any otherdesired allocation. Teleconference devices can both send and receivedata. All data transmission is fully time-scheduled. This way, there isno packet collision, backoff or resend, which reduces the effectivebandwidth. This assures no lost packets and extremely low latency. Theeffective bandwidth of HSSB is comparable to the 100BaseT networks. Theconference link 360 can also support daisy-chaining (connection inseries), which minimizes cabling while maximizing coverage. The systemmay also be installed in parallel, depending on the conference roomconfiguration. The HSSB links may be a combination of connections inseries or in parallel.

In accordance with one embodiment of the present invention, this highdata bandwidth is especially valuable because it allows the exchange ofmore than just audio signals. Indeed, video signals, control data, andintermediate data streams can be exchanged. Therefore, significantprocessing resources can be distributed through the system, not just ina set-top or a room processing module. This is, in effect, a meshcomputing network: an immensely flexible system architecture becauseprocessing can be scaled to match customer requirements, and a basicsystem does not need to be expensively over-designed to protect againstpossible future needs. Additional functions and additional processingcan be added, when and where needed, as requirements develop. Manyfunctions, resources or controls may be distributed among the linkeddevices, as discussed below.

The data transmitted between the units are in data packets. Each packetmay include several 16-bit words, typically two to eight words. Eachword may represent the digitized data for one audio channel, one controlcommand or one response. The transmitting and receiving packet rates areequal. In one embodiment, the digital link 360 is implemented in amaster/slave protocol, for example, the video unit is a master, and thespeakerphone is a slave. The communication between them is asymmetric.

Communication Protocol

As an example, the following packet format may be implemented.

The transmit packet format may be as follows: Bit 0 Start Bit 1-2 PacketType Bit 3-5 Address Bit 6-10 Transmit payload length (16 bit words) Bit11-15 Receive payload length (16 bit words) Bit 16-N Payload Bit N + 1Stop Bit

The packet type may be: Type 0 Set Address Type 1 Link Device DetectType 2 Normal transaction Type 3 Global Command

The payload length field can be zero indicating that no response isrequired/expected. Maximum payload length is 31 words which representsapproximately 65% of the total available bandwidth.

Packet type 0 is sent periodically to allow the slave devices to settheir address. No response is expected for this transmission type. Aseach link unit receives this field in increments the value by one beforesending it upstream. For example, the first unit in the link willreceive address 0 and send address 1, etc. The received addresscorresponds to the unit's link address. For the set address packet theaddress field is sent in bit reversed order to allow for a single bitlatency for shipping data upstream. The LSB of the address (firstaddress bit received) will always be inverted. If this bit were a one, acarry flag will be set and used to invert the next bit. This procedureis continued for all three address bits.

The set address packets are sent periodically when not in a call toallow for customer hot plugging of devices.

Packet type 1 is used to query the devices to determine what devicetypes are present. The response to this transmission would be a packetwith a single 16 bit payload that describes the device type, revisionlevel, etc. These packets would also need to be sent periodically toallow for hot plug scenarios where the customer adds another device tothe chain. A packet of type 1 will need to be sent to each possibleaddress. A no-response indication can be used to determine if a slavedevice is at the address.

Packet type 2 indicates that a normal data packet transaction isrequired.

Packet type 3 is reserved for global commands to all devices on thelink. No response is required for this packet type.

In the transmit/receive packet scheme, the receive packet format isdetermined by the transmit packet type. The receive packet ispredominately payload. Only the start message preamble and a stop bitare required in addition to the payload.

Receive packet format: Bit 0-1 Start bits Bit 2 Alignment bit Bit 3-NPayload Bit N + 1 Stop bit

Within the HSSB interface, there may be a buffer area for outbound dataand a buffer area for inbound data. For example, a 512 Byte SRAMlocation may be partitioned as two 256 Byte buffers. Since the maximumnumber of bytes transferable during a 48 KHz time period is 96 bytes,only the first 96 bytes of each buffer would need to be read/updated.

The downstream packet does not contain payload lengths, packet type,etc. This information will be auto-inserted into the receive header. Thehardware will also insert a zero word at the end of the receive messagelist. The message length (number of 16 bit words) will be 1+payloadlength. The transmit payload length field would be used to determinetransmit message length, the receive payload length will be used todetermine the receive payload length. If a response time out isencountered, the MSB of the receive header will be set.

Payload Data Packet

In one embodiment, the speakerphone, the slave device, can receivepackets with two words, one for audio data and one for control data. Thevideo unit may send packets with up to three words, with two audio wordsfor two audio channels and one control word.

The 16-bit control word RCW15-RCW0 has two reserved bits RCW15-14, sixmessage type bits RCW13-8 and eight control data bits RCW7-0.

Some sample of message types are illustrated in the Table 1 below: TABLE1 RCW₁₃ . . . RCW₈ Value Message Type 0x00 No data/No operation 0x01Command data 0x02 Sync data 0x03 Reserved for future use . . . 0x07 0x08LCD control data 0x09 Reserved for future use 0x0A Automatic dialingdata 0x0B Reserved for future use . . . 0x0F 0x10 “Write” register data.Bits . RCW₁₁ . . . RCW₈ give the register index. . . 0x1F 0x20 LCDdisplay data. Bits RCW₁₂ . . . RCW₈ . provide the x-axis index for thedisplay . position. . 0x3F

Some sample control data are illustrated in Table 2 below: TABLE 2Message Type RCW₇ . . . RCW₀ Usage Command Data Command byte Sync DataSync pattern (e.g. 0x5A) LCD Control Data LCD control byte AutomaticDialing ASCII byte (NULL-terminated string sent Data bytewise) “Write”Register Data Byte value to write to register Display Data 1 characteror 8 pixels

The packets from speakerphone to video unit contain the same type ofwords, except that there are more audio data words. There are up toeight 16-bit words in a packet sent from a speakerphone to a video unitusing the conference link 360. The aux, audio and control words aresimilar to the words in a packet sent from a video unit to aspeakerphone. The other six audio data words are used when thespeakerphone or the combined system uses additional audio channels. Ifnot, these audio data words may be used for generic data communication,e.g. video data video processing.

Audio Data Processing

FIG. 19 depicts a flow diagram of how the data packets are processed.There are several major blocks: HSSB Task 1901, Keypad Evt 1903, UI1905, Control Word 1913, System 1931, Audio sig task 1921, and SysControl 1941.

The Audio Sig task 1921 reads input packets and writes output packets,which together form the physical interface, e.g. HSSB interface 549 asshown in FIG. 5B, for HSSB payload content coming from or going to thesystem. The Audio Sig task 1921 may have two buffers, one for inputpackets and one for output packets. All software-controlled HSSB audiocontent is consumed or produced locally in the Audio Sig (or Audio LEC)task 1921, but HSSB control words are produced and consumed in the HSSBtask 1901, and are communicated between the two tasks via the ControlWord Queues 1913.

Input HSSB payloads are read by the Audio Sig task 1921. The receivedcontrol word is placed in the queue, and later processed by the HSSBtask 1901, possibly with the involvement of other software components.Control data messages follow the communication pathways shown in thefollowing Table 3. TABLE 3 Input packet processing Rx Control Data TypeCommunication Sequence Command Data 2, 1, 4 Sync Data 2, 1, LCD ControlData 2, 1, 4 Automatic Dialing Data 2, 1, 4 “Write” Register Data 2, 1,4 Display Data 2, 1, 4 Link Detect 4 (no HSSB message)

Outgoing control words are constructed by the HSSB task 1901 and placedin the queue. From there, they are added to the outgoing HSSB payloadswhen the Audio Sig task 1921 writes. On their way out, the variouscontrol data messages follow the processing pathways (from FIG. 15)given in Table 4 below: TABLE 4 Output packet Tx Control Data TypeCommunication Sequence Command Ack 1, 2 Sync Data 1, 2 Caller ID Data 7,4 1, 2 Keypad Data 5, 3, 1, 2 Call Status 7, 4 1, 2 Software Version 1,2 Hardware Version 4, 1, 2 LCD Control Ack 1, 2 Mic Calibration Data 4,1, 2 Automatic Dialing Data 4, 1, 2 Video Call Request 5, 4, 1, 2 ManualDialing Data 5, 3, 1, 2 Local Phone Number 4, 1, 2 “Read” Register Data4, 1, 2

Thus, in addition to carrying audio data between linked conferencingdevices, the HSSB may carry control and status data in accordance withthe present invention. When the video conference unit 400 and thespeakerphone 500 are connected with HSSB 360, control and status datamay be transmitted between the connected devices. The dialing and otherconference control may be made from the dial-pad on the speakerphone500. The dial-pad command is sent to the video conference unit 400embedded in the control word in the data packet from the speakerphone500 to the video conference unit 400. The status data, including videoconference status is returned to the speakerphone 500 in a similarcontrol word in a return data packet. The conference status may bedisplayed on an LCD display on the speakerphone 500. The dial-pad on thespeakerphone 500 may be used to control both the video conference unit400 and the speakerphone 500. This way, the remote control for the videoconference unit 400 is not needed when setting up a video conferencecall.

In accordance with another embodiment of the present invention, signalsincluding audio signals and control signals may be exchanged accordingto a Low Profile Signaling Protocol (“LPSP”). An exemplary conferencingsystem in accordance with a LPSP-based protocol is shown in FIGS. 6A and6B. The diagrams of FIGS. 6A and 6B illustrate an exemplary architecturefor providing digital data over an existing audio channel 620 viain-band signaling, in accordance with an embodiment of the presentinvention.

The endpoint 12 of FIG. 1 may be embodied as the local endpoint 600 ofFIG. 6A, and the endpoint 14 of FIG. 1A may be embodied as the remoteendpoint 601 of FIG. 6B. Any of the endpoints 24, 25, and 26 of FIG. 2may be embodied as the local endpoint 600 or the remote endpoint 601 ofFIGS. 6A and 6B.

The local endpoint 600 exchanges audio signals with a remote endpoint601 via the audio channel 620, which may be a POTS line, or a cableline, etc. In order to send digital data in addition to the conventionalaudio signals over the same audio channel 620, a low data-rate data“connection” is embedded within an existing narrow-band connection.Utilizing this process to transmit data during audio communication,various types of data aside from the conventional audio data can beexchanged by way of embedded digital data. For example, conferencerelated data, such as spreadsheets, slide presentations, or diagrams,etc., can be exchanged between the local endpoint 600 and the remoteendpoint 601 to enable collaborative conferencing.

As a more specific example, output from medical devices or any otherdevices can be sent to an expert during a phone call by personsattending to the medical devices. By this feature, the expert canreceive pertinent data while on the phone call in which the expert maybe providing instructions to persons located in proximity to the medicaldevices based on the data being received by the expert. Numerousapplications of the process of transmitting data during audiocommunication using embedded digital signals are possible. Further,utilizing the system described herein to send data over the audiochannel 620 avoids interruptions to the phone call. Thus, usersexperience no noticeable call noise or interruption as a result ofsending digital data over the audio channel 620.

As another example, the digital data being transmitted to the remoteendpoint 601 may be of an image from a whiteboard. Thus, as the localendpoint 600 transmits audio signals to the remote endpoint 601, digitaldata is also transmitted over the audio channel 620. The digital dataincludes images from the whiteboard at the site of the local endpoint600, thus allowing the remote endpoint 601 to reproduce the images on adisplay medium associated with the remote endpoint 601.

The data from the whiteboard can be communicated to the local endpoint600 via any type of connection suitable for use with the presentinvention, such as via a 232 link. The local endpoint 600 receives thedata from the whiteboard and the local data processing engine 603packages the data for transmission via the audio channel 620.

Any device may be coupled to the local endpoint 600 for providing datato the local endpoint 600, receiving data from the local endpoint 600,etc. in accordance with the present invention. For example, a computingdevice, such as a personal computer, may optionally be associated withand/or coupled to the remote endpoint 104. The computing device canprocess and play the audio data from the audio signals. Further, in thepresent example, the computing device can utilize a projector to displaythe digital data received from the whiteboard onto the display medium,such as a whiteboard, screen, etc. associated with the remote endpoint601. Alternatively, the images from the whiteboard received via thedigital data transmitted during the audio communication may be displayedon a display medium of the computing device itself.

Conversely, the projector may utilize the audio channel 620 to forwarddigital data back to the local endpoint 600. For example, the projector,via the computing device and the remote endpoint 601 can forward digitaldata to the local endpoint 600 during audio communication indicatingthat a packet was not received. Alternatively, other devices may becoupled to the local endpoint 600 and the remote endpoint 601 forproviding and displaying various types of digital data transmitted viathe audio channel 620.

Furthermore, control signal data may be sent between the local endpoint600 and the remote endpoint 601. The control signals may include, forexample, instructions from endpoint 600 to adjust the microphone levelor loudspeaker volume of endpoint 601, or vice versa. As anotherexample, the control signals may include instructions sent by one of theendpoints to mute all other participants. The control signals mayfurther provide instructions that the far endpoint establish a newconnection, such as an IP connection to a website, or provide a passwordor a URL to the far endpoint. One use for transferring a password may beto secure a link. In multipoint conferencing, the control signals mayalso include instructions for a bridge to dial a specific phone number,provide billing information such as cost of the conference so far,monitor the number of conference participants, or collect pollinginformation from conference participants.

Referring again to FIG. 6A, the local endpoint 600 receives data, andprepares the data for transmission to the remote endpoint 601 via theaudio channel 620. A microphone 602 collects audio data and converts theaudio data into an audio signal in the local endpoint 600. The audiosignal is then fed into an amplifier 604 for adjustment.

According to one embodiment, as discussed in further detail below, aportion of the audio signal may then be filtered out using a notchfilter technique. In other words, the audio signal may be passed througha notch filter, which removes audio signal content in a spectral regionwhere a modulated carrier signal will exist, as discussed herein. Thus,the notch filter creates a notch in the audio signal frequency spectrumfor embedding the digital data.

In alternative embodiments, the notch filter creates multiple notches inthe audio signal frequency spectrum. The remaining portion of the audiosignal frequency spectrum is utilized for the transmission ofconventional audio data. Typically, the section of the audio signalfrequency spectrum removed via the notch filter is as little as possibleand at a higher end of the frequency spectrum typically inaudible tohuman ears. A carrier signal is then created and digital data ismodulated onto the carrier signal to create a modulated carrier signal,which is subsequently embedded in the notch.

In another embodiment, the audio signal is prepared in advance utilizinga spread spectrum module that modulates the digital data onto thecarrier signal. The spread spectrum module varies the frequency of thecarrier signal across the audio signal. Accordingly, the digital data ismodulated onto the carrier signal, which is either spread across theaudio signal utilizing the spread spectrum module or embedded into theaudio signal in the notch of the audio signal created by the notchfilter.

Alternatively, the audio signal may not require preparation. Adirect-sequence spread spectrum signal can be added directly to theunprepared audio signal. Further, a frequency-hopping signal, forinstance, may or may not require pre-notching of the audio signal at ahopping frequency. Thus, in some embodiments, the audio signal requireslittle or no preparation in order to be combined with the modulatedcarrier signal.

In either above-described embodiment, a data source 606 provides thedigital data to be forwarded via the audio channel 620. The data source606 may include any suitable source of data. For example, the data maybe from an internal source, such as a source of data within a particularcompany, a 232 link, etc. For instance, an internal source of the datamay be data from a whiteboard.

Next, a carrier signal generator generates a carrier signal. A carriersignal modulator/demodulator 608 then modulates the digital data fromthe data source 606 or control data from the local data managementengine 614 onto the carrier signal, as discussed herein. The carriersignal modulator/demodulator 608 can also demodulate incoming modulatedcarrier signals received from the one or more remote endpoints 601, orany other device suitable for use with the present invention. In thepresent embodiment, the carrier signal is generated by the localendpoint 600; however, the carrier signal may be obtained from anysuitable source. Further, any type of modulation suitable for use withthe present invention may be employed, such as amplitude modulation,quadrature phase modulation, phase or differential phase modulation,etc.

Subsequently, a product signal generator 610 creates a product signalcomprising the audio signal combined with the modulated carrier signal.The modulated carrier signal is typically added to the audio signal at avery low amplitude. Low amplitude can be accomplished by pre-notchingthe audio signal at the modulated carrier signal frequency, as discussedherein. Resultantly, the modulated carrier signal has a low amplituderelative to audio amplitudes surrounding the modulated carrier signalamplitude, making the modulated carrier signal amplitude undetectable bya human ear. Accordingly, the modulated carrier signal is substantiallyinaudible to, or “masked” from, the ordinary listener. Further, soundsthat are in a spectral proximity to a target signal typically render thetarget signal inaudible. Thus, the modulated carrier signal (i.e.,target signal) is masked by the audio signal (i.e., sounds) in which themodulated carrier signal is embedded.

In one embodiment, the modulated carrier signal is modulated toward theupper end of the bandwidth spectrum, such as 3 kHz. Because the ear isless sensitive to signals at this end of the spectrum, the modulatedcarrier signal is inaudible to the ordinary listener. Further, themodulated carrier signal has a narrow bandwidth, as discussed herein,which allows the notching of the audio signal to be correspondinglynarrow, and to thus have no perceptible effect on the audio signal.

A local communication interface 612 forwards the product signal to oneor more remote endpoints 601 via the audio channel 620. Any suitabletransmission medium may be employed for communicating the product signalto the one or more remote endpoint 601.

Because the carrier signal is added to the audio signal utilizing thenotch filter technique or the spread spectrum technique describedherein, users of a phone line experience no call interruption, aspreviously discussed. Accordingly, users can exchange data in additionto the normal audio signal data being carried over the phone linewithout experiencing any noticeable call interruption and without havingto establish multiple communication channels. It is understood that thisis merely one example of the use of the present invention. Other devicesmay be utilized to communicate other types of data. For example,overhead projectors, computers, video cameras, etc. may be utilized tocommunicate data via the carrier signal.

As discussed herein, the carrier signal modulator/demodulator 608 canalso demodulate incoming modulated carrier signals. Once the digitaldata has been extracted from the incoming modulated carrier signal bythe carrier signal modulator/demodulator 608, the digital data isforwarded to a local data management engine 614. An exemplary embodimentof a data management engine is shown in FIG. 6C. Although theperspective from the local endpoint 600 or the remote endpoint 601 isutilized at certain parts of this discussion for purposes of simplicity,the local endpoint 600 and the remote endpoint 601 are capable ofperforming identical or similar functions, due to the bi-directionalnature of communication, in accordance with the present invention.

A local communication interface 612 forwards the product signal to oneor more remote endpoints 601 via the audio channel 620. Any suitabletransmission medium may be employed for communicating the product signalto the one or more remote endpoints 601.

The audio signal with the modulated carrier signal is received by theone or more remote endpoints 601 via a remote communication interface302. The remote data processing engine 605 at the remote endpoint 601recovers the product signal and the product signal module 654 separatesthe audio signal from the modulated carrier signal. The audio signal istypically amplified by the amplifier 656 and played via a loudspeakerassociated with the remote endpoint 601. The carrier signal isdemodulated by the carrier signal modulator/demodulator 658 and thedigital data is processed. For example, it may be displayed via adisplay medium (not shown) associated with the remote endpoint 601,utilized by the remote endpoint 601, etc.

Once the digital data is recovered by the carrier signalmodulator/demodulator 658, the digital data is forwarded to the remotedata management engine 664. As discussed herein, the remote datamanagement engine 664 can control functions, devices, etc. associatedwith an audio conference occurring via the audio channel 620, inresponse to the control data received. For instance, the remote datamanagement engine 664 may instruct other devices participating in theaudio conference, or itself, to adjust volume, mute some or allparticipants, request hangup status, request participant polling data,request billing information, etc. Other devices participating in theconference may include, for instance, other communication devices, anaudio bridge, a video device, a multimedia conference bridge,projectors, the network itself, etc.

Because communication is bidirectional, the remote endpoint 601 canforward digital data including control data to the local endpoint 600and/or other devices by modulating digital data from a data source 662onto a carrier signal via the carrier signal modulator/demodulator 658.The product signal module 654 combines the modulated carrier signal withthe audio signal received via the microphone 660 and amplified via theamplifier 656. The product signal is then forwarded to the localendpoint 600 and/or any other device via the audio channel 620.Alternatively, the digital data, audio signal, and/or product signal canbe forwarded to the local endpoint 600 and/or any other device via oneor more new communication channels established by the communicationchannel generator at the local endpoint 600 or a communication channelgenerator at the remote endpoint 601.

The remote data management engine 664 includes a data router module 670,a device control module 672, a communication channel generator 674, andan output module 676 as shown in FIG. 6C. Upon receipt of the productsignal, the carrier signal modulator/demodulator 658 extracts thedigital data from the modulated carrier signal and forwards the digitaldata to the remote data management engine 664, as discussed herein.

The data router module 670 examines the digital data and determineswhether to forward the data to the device control module 672, thecommunication channel generator 674, and/or the output module 676. Thedata router module 670 may make the determination based on the contentof the digital data, itself, a header associated with the digital data,etc. The data router module 670 forwards the data to one or more of theappropriate modules and/or based on the nature of the data. Forinstance, data that does not require any further action to be taken inresponse to the data itself, other than display of the data, may only beforwarded to the output module 676.

The device control module 672 creates instructions based on the datareceived from the data router module 670. The instructions generated bythe device control module 672 can translate the data into controlcommands in order to control one or more devices associated with theremote endpoint 601 and/or the remote endpoint 601, itself. Forinstance, the device control module may instruct, via a control command,one or more devices to adjust volume. As another example, the devicecontrol module may instruct one or more devices to become muted. Anycontrol command or other instruction for controlling any deviceassociated with the remote endpoint 601 and/or any other deviceassociated with the audio channel 620 is within the scope of the presentinvention. The device control module 672 can also forward the digitaldata, control commands, instructions, feedback, etc. to the data routermodule 670, the communication channel generator 674, and/or the outputmodule 676 for further processing.

The communication channel generator 674 creates at least one newcommunication channel in response to the data received from the datarouter module 670, the device control module 672, and/or the outputmodule 676. Alternatively, the remote communication channel generator674 can send information pertinent to establishing the at least one newcommunication channel to the remote endpoint 601, itself, the localendpoint 600, and/or another device associated with the existing audiochannel 620. For instance, the communication channel generator 674 canprovide a meeting location, session identification, password, etc. thatenables the at least one new communication channel to be successfullyopened and data to be exchanged over the new communication channel.

As discussed herein, the data communicated via the audio channel 620 isas secure as the audio channel 620 itself. Thus, unless the security ofthe audio channel 620 has been breached in some manner, the dataprovided via the audio channel, such as a password, is protected.

The output module 676 determines an output medium for the data receivedvia the data router module 670, the device control module 672, and/orthe communication channel generator 674. The output module 676 mayoutput the data via any medium suitable for use with the presentinvention. For instance, the data may be output via a screen, such as anLCD screen associated with a telephone, a computer screen, etc.,associated with the local endpoint 600, the remote endpoint 601, and/orany other device associated with the existing audio channel 620. Asanother example, the data may be output via a speaker associated withthe local endpoint 600, the remote endpoint 601, and/or any other deviceassociated with the existing audio channel 620. Any method of outputtingthe data is within the scope of the present invention.

In accordance with one embodiment of the present invention, data may bemodulated by a spread-spectrum modulator, and then added onto the audiosignal at low amplitude but over all or a substantial part of the audiobandwidth. Such modulation causes the spectrum of the data to spread, sothe sound is of a small amount of added noise in the audio.

Some audio signals, such as speech, have the characteristic that theiramplitude changes frequency. In these cases, it is desirable to adjustthe amplitude of the data component before combining it with the audiosignal, in order to have the data component maintain a fairly constantamplitude relative to the amplitude of the audio signal This produces anoptimal signal-to-noise ratio of the data signal for a given level ofmasking. It will be noted that this variation in amplitude cannot bemade too quickly lest it be confused with the data modulation itself,but it turns out that the amplitude can be adjusted slowly (for example,10 Hz amplitude adjustment bandwidth) relative to the modulating datarate, without degrading the masking effect on the audio, the quality ofthe audio or the reliability of the digital data.

In another implementation, the single-frequency carrier can be replacedwith any common spread-spectrum implementation, such as afrequency-hopping or direct-sequence technique. This has the advantageof appearing as noise which is then added to the audio signal. It shouldbe noted that the use of a spread-spectrum signal within the narrowaudio bandwidth is itself new and novel. This has the advantage of notconcentrating the digital data within a narrow spectral band, which canrender it even less noticeable.

Reference is now made to FIG. 7, which depicts an exemplary audioconferencing system using a spread spectrum technique. At least onemicrophone 702 or acoustic device collects audio data and converts theaudio data into an audio signal, which is then passed through anamplifier 704. Digital data is also received from a data source 706. Inthis embodiment, a spread spectrum carrier wave is generated by a spreadspectrum carrier wave generator 708 and provided to a modulator 710. Themodulator 710 is utilized to modulate the digital data from the datasource 706 onto the spread spectrum carrier wave, which is subsequentlycombined with the audio signal by a product signal module 712.

In one embodiment, the digital data from the data source 706 ismodulated onto the audio signal at a low amplitude and over all or asubstantial portion of bandwidth of the audio signal. Accordingly, theproduct signal module 712 causes the spectrum of the spread spectrumcarrier wave to spread over all or a portion of the bandwidth of theaudio signal, so the added noise from the digital data is small enoughto be undetectable to the ordinary listener. Any suitable spreadspectrum technique may be utilized in accordance with the presentinvention. For example, an ultrasonic spread spectrum technique or anaudio spread spectrum technique may be utilized.

A local communication interface 714 at the local endpoint 700 forwardsthe product signal or combined signal to the remote endpoint 701 via thetransmission medium 716, such as a PSTN, by way of the audio channel(such as the audio channel 620 of FIG. 6A). The remote endpoint 701,upon receipt of the product signal, filters the product signal andseparates the audio signal from the modulated carrier signal.Subsequently, the audio signal data is output via an output mediumassociated with the remote endpoint 701, such as a loudspeaker. Thedigital data from the data source 706 is extracted and processed. Thedata may be output via a data output medium associated with the remoteendpoint 701, such as a display medium.

Referring now to FIGS. 8 through 10, an exemplary spread spectrumtechnique is depicted. FIG. 8 illustrates a conventional audio signal800. FIG. 9 illustrates a carrier signal 900 including digital data fromthe data source 706 of FIG. 7. FIG. 10 illustrates the modulated carriersignal 900 combined with the audio signal 800 to create a product signalor combined signal 1000 having the modulated carrier signal 900 spreadacross all or a portion of the bandwidth of the audio signal 800.

In one embodiment, the amplitude of the digital data from the datasource 706 is adjusted before combining the digital data with the audiosignal to create the product signal. In this embodiment, the productsignal maintains a fairly constant amplitude relative to the amplitudeof the audio signal. An optimal signal-to-noise ratio of the data signalfor a given level of masking is maintained by maintaining the fairlyconstant amplitude of the modulated carrier signal relative to theamplitude of the audio signal. The amplitude of the modulated carriersignal is typically adjusted slowly relative to the modulating data ratein order to prevent degrading of the masking effect on the audio,quality of the audio, or reliability of the digital data.

In another embodiment of the present invention, a single-frequencycarrier can be replaced with any common spread-spectrum implementation,such as a frequency-hopping or direct-sequence technique. Replacing thesingle-frequency carrier with the common spread-spectrum implementationmay create the appearance of noise, which can then be added to the audiosignal. The added noise is uniform and at a lower level than the audiosignal. Thus, the audio signal retains its full bandwidth, with someadded background noise, instead of clipping part of the bandwidthcompletely, as with the notch filter 306.

Reference is now made to FIGS. 11A and 11B, which depict a conferencingsystem for sending digital data over the audio channel (such as theaudio channel 620 of FIG. 6A) in accordance with an alternativeembodiment of the present invention. In this example, a local endpoint1100 prepares the digital data for transmission to one or more remoteendpoints 1101 via the audio channel. At least one microphone 1102 orother acoustic device collects audio data and converts the audio datainto an audio signal. The audio signal is then fed into an amplifier1104 for adjustment.

A portion of the audio signal is then filtered out by a notch filter1106. In other words, the audio signal is passed through the notchfilter 1106, which removes content in a spectral region where amodulated carrier signal will exist, as discussed herein. The notchfilter 1106 creates a subset of the audio signal frequency spectrum forforwarding the digital data.

In an alternative embodiment, the notch filter 1106 creates multiplesubsets of the audio signal frequency spectrum. The remaining portion ofthe audio signal frequency spectrum is utilized for the transmission ofnormal audio data. Typically, the portion of the audio signal frequencyspectrum removed via the notch filter 1106 is as little as possible andat the higher end of the frequency spectrum. For example, a 3000 to 3100Hertz (Hz) portion of the frequency spectrum of a conventional phoneline, which accommodates data between 300 to 3300 Hz, may be reservedfor sending data across the audio channel.

A data source 1108 provides digital data to be forwarded via the audiochannel. This data may include, but is not limited to, data from awhiteboard, a projector, a computing device, etc. This data may furtherinclude control data as described above. A signal generator 1112 createsa carrier signal, which is forwarded to a modulator 1110. The modulator1110 then modulates the digital data from the data source 1108 onto thecarrier signal. In one embodiment, the modulator 1110 determines thespectrum associated with the audio signal. Any type of modulationsuitable for use with the present invention may be employed, such asamplitude modulation, quadrature phase modulation, phase or differentialphase modulation, and so on.

Optionally, an amplitude adjustment module 1113 may be provided foradjusting the amplitude of the modulated carrier signal proportionallyto an instantaneous amplitude of the audio signal. The adjustment may bemade in a region of a spectrum near a region occupied by the modulatedcarrier signal.

Once modulated, the modulated carrier signal is forwarded to a productsignal module 1114 where a product signal of the audio signals combinedwith the modulated carrier signal is created. Accordingly, the modulatedcarrier signal is embedded into the audio signal in the portion of theaudio signal filtered out by the notch filter 1106. In the embodimenthaving multiple subsets of the audio signal reserved by the notch filter1106, multiple carrier signals are created and embedded into the audiosignal in the subsets of the audio signal frequency spectrum reservedtherefore. The modulated carrier signal is typically added to the audiosignal at a very low amplitude. Accordingly, the modulated carriersignal is substantially inaudible to, or “masked” from, the ordinarylistener. A local communication interface 1116 communicates the productsignal to the remote endpoint 1101 by way of the existing audio channelvia a transmission medium 1118. Any suitable transmission medium 1118may be utilized in accordance with the present invention.

The data source 1108 may include any suitable source of data. Forexample, the data may be from an internal source, such as a source ofdata within a particular company, a 232 link, etc. For instance, aninternal source of the data may be the data from a whiteboard, data froman internal server, data from a computing device, etc.

Referring now to FIG. 12, an exemplary audio signal frequency spectrum1200 is shown. As discussed herein, in order to send the digital data inaddition to the audio data being communicated via the audio signal, aportion of the audio signal frequency spectrum 1200 is reserved.Typically, a conventional phone line can accommodate data between 200 to3200 Hertz (Hz). A portion of that audio signal frequency spectrum 1200is reserved for sending data in addition to, and/or separate from, thenormal audio signals being carried across the audio channel. Forexample, the 3000 to 3100 Hz portion of the frequency spectrum may bereserved for sending data across the existing audio channel. However,reserving any portion of the audio signal frequency spectrum 1200 of theaudio signal is within the scope of the present invention. Whilereserving the portion of the audio signal frequency spectrum 1200 mayslightly diminish capacity for sending audio signals, this processallows for the exchange of additional data across the existing audiochannel. Advantageously, users of the phone line experience no callinterruption or distortion in the transmitted audio. Accordingly, userscan exchange data in addition to the normal audio signal data beingcarried over the audio channel without experiencing any noticeable callinterruption and without having to establish multiple communicationchannels. It is understood that this is merely one example of the use ofthe present invention. Other devices may be utilized to communicateother types of data. For example, overhead projectors, computers, videocameras, etc. may be utilized to communicate data via the carriersignal.

Referring now to FIG. 13, the audio signal frequency spectrum 1200 afterbeing filtered by the notch filter 1106 is shown. A portion 1300 of theaudio signal frequency spectrum 1200 has been filtered out by the notchfilter 1106. A modulated carrier signal 1400 is created for insertioninto the portion 1300 of the audio signal frequency spectrum 1200, asshown in FIG. 14.

Referring now to FIG. 15, a product signal 1500 in accordance with anembodiment of the present invention is shown. The product signal 1500 isthe combination of the audio signal frequency spectrum 1200, the audiosignal frequency spectrum 1200 portion 1300 filtered out by the notchfilter 1106 of FIG. 11A, and the modulated carrier signal 1400 insertedinto the portion 1300. As discussed herein, the product signal module1114 of FIG. 11A combines the audio signals and the modulated carriersignal 324. The product signal 1500 is then communicated to the remoteendpoint 1101 by the local communication interface 1116 of the localendpoint 1100 via a transmission medium 1118.

In one embodiment, the amplifier 1104 of FIG. 11A can adjust theamplitude of the modulated carrier signal 1400 proportionally to aninstantaneous amplitude of the audio signal 1200. In this embodiment,the adjustment may be made in a region of the spectrum occupied by themodulated carrier signal 1400.

Data Extraction by Remote Endpoint

The audio signal with the modulated carrier signal (i.e., product signal1500 of FIG. 15) is initially received by a remote communicationinterface 1152, and forwarded to a product signal module 1154, whichseparates the audio signal from the modulated carrier signal. The audiosignal may be output by the audio signal output module 1156. Forinstance, the audio signal may be amplified and played via a speakerassociated with the remote endpoint 1101. The speaker may be located inthe remote endpoint 1101 or, alternatively, the speaker may be externalto the remote endpoint 1101.

Substantially concurrently, the modulated carrier signal 1400 is sent toa demodulator 1158, which demodulates the modulated carrier signal 1400.Subsequently, the digital data is forwarded to a data output module1160, which can output the data to the user. For example, the data maybe displayed via a display medium associated with the remote endpoint1101, utilized by the remote endpoint 1101, etc. As discussed herein,the present system works in a bidirectional manner in order to respondto the digital data received from the local endpoint 1100 or tootherwise send data to the local endpoint 1100.

In accordance with one embodiment of the present invention, aspeakerphone device is provided that can send, transmit, and processcontrol data embedded with audio data according to any of theabove-described protocols (IP, modem, serial I/O, and LPSP). Thespeakerphone can send, transmit, and process signals over a PSTN. Thespeakerphone can send, transmit, and process signals over an IP-basednetwork. The speakerphone can provide narrowband audio and dataconferencing. The speakerphone can also provide wideband audio and dataconferencing.

An exemplary speakerphone 1800 is depicted in FIG. 18. The speakerphonedevice can control functions of a remote endpoint, including but notlimited to another speakerphone or a bridge. As control data isbidirectional, the speakerphone's functions can be controlled by aremote endpoint, including but not limited to another speakerphone or abridge.

Certain kinds of data are particularly well suited to sharing thechannel with voice. These tend to be kinds of data that supervise andmonitor the function and performance of voice-related devices. Forexample, the speakerphone 1800 can establish and control additionalcommunication channels and device from within an existing voice channel.Furthermore, the speakerphone 1800 can use an existing secure audioconnection to initiate a secure second connection. The speakerphone 1800can also command a conference bridge to collect polling information fromother conference participants, as described further above. Thespeakerphone 1800 can also send a password or URL information to anothertelephone. The speakerphone 1800 can also monitor the number ofparticipants on a bridge call by receiving this information from thebridge, as described further herein. In addition, the speakerphone 1800can facilitate VGA video and image collaboration by using phone-linedata to establish and manage a separate graphics connection.

In addition, the speakerphone 1800 can instruct the bridge to collectpolling, voting, or roll call information from the conferenceparticipants. For example, participants in an audio conference may voteon an issue or answer a question, by using DTMF or voice responses. Thebridge receives the responses and can provide a report of the results toone or more participants. Advantageously, the ability to providereal-time polling functionality provides immediate feedback and enablesquick decision making.

In addition, the bridge can allow a participant to monitor the numberand names of participants on an audio conference. For example, thebridge can send messages to a participant such as the supervisoridentifying the current number of participants (e.g., “Currently 3participants”). The bridge can also send messages to a participant suchas the supervisor, indicating the identity and/or location of theparticipants (e.g., “Currently 3 participants: Polycom-Austin;Polycom-Milpitas; and Polycom-Andover”). The messages can be sent atregular intervals (e.g., every minute). The messages can also be sentupon request by an endpoint. The messages can also be sent wheneverthere is a change in the number of participants. In addition, whenever aparticipant joins the conference, the bridge can send messages to aparticipant such as the supervisor, indicating who has just joined theconference (e.g., “Polycom-Pleasanton has joined”). Whenever aparticipant leaves the conference, the bridge can send messages to aparticipant such as the supervisor, indicating who has just left theconference (e.g., “Polycom-Milpitas has left”).

In addition, the speakerphone 1800 can implement LPSP to add a varietyof features, such as IP-like applications, e.g., polling, talkeridentification, volume control, etc. As another example, the voiceconnection is the most straightforward place to embed data related tothat voice channel. A conference participant may be in a conference roomwith multiple microphones, and it may be useful to embed informationspecifying which microphone is being selected at each moment to aid intalker identification.

The foregoing are illustrative examples of control functions wherein aspeakerphone may control or be controlled by another endpoint includinga bridge. The foregoing examples are illustrative only and are notintended to be exhaustive. It will be appreciated by one skilled in theart that additional types of control functions are within the scope ofthe present invention.

Reference is now made to FIG. 16, which depicts an exemplary blockdiagram illustrating a general description of a conference environment1600 including endpoints 1610 aa-nk, operator 1615, multimedia signals1620 aa-nk, multimedia signals 1622 a-k, networks 1630 a-k, and bridge1640. In one exemplary embodiment, the bridge 1640 may include a networkinterface (“NI”) 1642, Compressed Audio Common Interface (“CACI”) 1650,audio unit 1660, Management and Control System (“MCS”) 1670, controlsignals 1674, embedded data unit 1678, host 1680, and video unit 1690.Other exemplary embodiments may not have a video section and may be usedfor audio conferences only.

The pluralities of endpoints 1610aa-nk are connected via the pluralityof networks 1630a-k to the bridge 1640. The bridge 1640 may be an MCU,or an audio only multipoint control unit (an audio bridge), for example.The bridge 1640 and/or some or all of its components are logical unitsthat may be implemented by hardware and/or software and/or firmware. TheMCS 1670 may be a control module and may be a logical unit that controlsthe operation of the bridge 1640.

The endpoints 1610 aa-nk comprise terminals on a network, capable ofproviding one-way or two-way audio and/or visual communication withother terminals or with the bridge 1640. The information communicatedbetween the terminals and/or the bridge 1640 may include control signals1674, indicators, audio information, video information, and data. Aterminal may provide any combination of several different types ofinputs and/or outputs, such as speech only, speech and data, acombination of speech and video, or a combination of speech, data, andvideo.

The network interface 1642 receives multimedia communications 1622 a-kvia a plurality of networks 1630 a-k and multimedia signals 1620 aa-nkfrom the plurality of the endpoints 1610 aa-nk, and processes themultimedia communication according to communication standards that areused by each type of network, such as, but not limited to, H.323, H.321,SIP, and/or H.320. The network interface 1642 then delivers compressedaudio, compressed video, compressed data, and control streams toappropriate logical modules in the bridge 1640. Some communicationstandards require that the process of the network interface 1642 includedemultiplexing the incoming multimedia communication into compressedaudio, compressed video, compressed data, and control streams. In theopposite direction, the network interface 1642 receives the separatestreams from the various units (e.g., the MCS 1670, audio unit 1660,and/or video unit 1690) and processes the streams according to theappropriate communication standard. The network interface 1642 thentransmits the streams to the appropriate network 1630 a-k.

The audio unit 1660 receives the compressed audio streams of theplurality of endpoints 1610 aa-nk via the network interface 1642 andCACI 1650, processes the audio streams, mixes the relevant audiostreams, and sends the compressed mixed signal via the CACI 1650 and thenetwork interface 1642 to the endpoints 1610 aa-nk. Audio unit 1660 maybe a logical unit and is described in more detail below in conjunctionwith FIG. 17.

The video unit 1690 may be a logical unit that receives and sendscompressed video streams. The video unit 1690 includes at least onevideo input module that handles an input portion of a video stream 1692from a participating endpoint and at least one video output module thatgenerates a composed compressed video output stream that is sent viaCompressed Video Common Interface (“CVCI”) 1692 to network interface1642 and from there to the designated endpoints 1610 aa-nk.

The uncompressed video data is shared by input and output modules on acommon interface such as, but not limited to, Time Division Multiplexing(“TDM”), Asynchronous Transfer Mode (“ATM”), and/or shared memory. Thedata on the common interface may be fully uncompressed or even partiallycompressed. An exemplary operation of such a video unit is described inU.S. Pat. No. 6,300,973, the contents of which are incorporated hereinby reference.

The host 1680 communicates with the operator 1615 of the bridge 1640.The operator 1615 may have an operator's station for communicating withthe host 1680. The host 1680 controls the bridge 1640 via the MCS 1670according to instructions from the operator 1615.

FIG. 17 depicts an exemplary block diagram of an embodiment of thepresent invention including a more detailed description of the audiounit 1660 and the embedded data unit 1678 of FIG. 16.

The audio unit 1660 includes compressed signals 1715 and 1717, codecs1720, decoded information 1726, mixed output 1728, and signal processingunit 1750. Each codec 1720 includes a decoder 1722 and an encoder 1724.The signal processing unit 1750 includes an analyze and enhance unit1752, information signal 1753, control unit 1754, switch 1756, controlsignals 1757, selected signals 1759, mixer 1760, and mixed signal 1761.Compressed audio streams from all endpoints that are connected to an MCUare transferred over the CACI 1650. The MCS 1670 allocates the codec1720 to one of the endpoints 1610 aa-nk (FIG. 16).

Further, the CACI 1650 carries signals to and from endpoints 1610 aa-nk.For example, the compressed signal 1715 from one of the endpoints 1610aa-nk is routed through the CACI 1650 to the decoder 1722 in the codec1720, which was previously allocated to that endpoint by the MCS 1670via control bus 1735.

The decoder 1722 may be a logical unit and may decode a compressed audiostream, based on communication standards such as, but not limited to,G.723.1, G.728, G.729, and MPEG. The decoder 1722 then decodes thecompressed audio stream, such as compressed signal 1715, and broadcaststhe decoded signal 1726 over the Decoded Audio Common Interface (“DACI”)1740.

The DACI 1740 is a bus that may have broadcasting capabilities. The DACI1740 may be implemented for example by any one of or any combination ofTime Division Multiplexing (TDM), Asynchronous Transmission Mode (ATM),Local Area Network (LAN), wireless technology, or shared memory. Thesignal processing unit 150 may then grab the decoded signal from theDACI 1740 and may analyze, enhance, and/or mix the decoded signal andreturn the output 1761 to the DACI 1740.

The encoder 1724 may be a logical unit and may be an enhancement and/orencoding unit. The encoder 1724 may compress the output 1728 of theappropriate signal processing unit 1750 forming a compressed audiostream, such as the compressed signal 1717, based on the communicationstandard such as, but not limited to, G.723.1, G.728, G.729, and/orMotion Picture Expert Group (“MPEG”).

The MCS 1670 generates a Cross-Conferences Database (“CCDB”) based onthe required setup of all the participants and all the conferences thatcurrently exist in the MCU. The CCDB is a Cross-Conference Database thatholds the connection parameters (e.g., codecs and processing units,etc.) and the connection status (e.g., Normal, Mute, etc.) of eachendpoint (participant) that is currently connected to the MCU, in everyconference that is currently managed by the MCU. The CCDB enables theparticipation of at least one participant in more than one conference.According to the CCDB, the MCS 1670 programs one or more signalprocessing units 1750 to grab from the DACI 1740 the decoded signals ofall the participants associated with a conference that is assigned tothose signal processing units 1750.

The decoded output of any codec 120 can be grabbed by more than onesignal processing unit 1750, allowing the participants to be associatedwith more than one conference. The decoded streams from the decoders1722 on the DACI 1740 may be grabbed by the signal processing unit 1750and then analyzed and enhanced by the analyze and enhance unit 1752.

The analyze and enhance unit 1752 may be a logical unit, and may includea set of algorithms for analyzing an audio stream of a participantand/or enhancing its quality, such as, but not limited to, InternationalTelecommunications Union (ITU) G.165 (echo canceling), Dual ToneMulti-Frequency (DTMF) suppression, noise reduction, and/or VoiceActivity Detector (VAD).

The signal processing unit 1750 may have one or more analyze and enhanceunits 1752. Each analyze and enhance unit 1752 may be assigned to asingle participant and programmed according to the connection status ofthat participant in the conference.

The control unit 1754 controls a conference that receives all signalsfrom the analyze and enhance unit 1752 and selects the participants thatwill be routed via switch 1756 to the mixer 1760. The mixer 1760receives the enhanced streams from all of the selected participants andsupplies each participant with an uncompressed mixed audio stream of theselected participants. Signals from the analyze and enhance unit 1752are sent to the control unit 1754, and the enhanced decoded audiosignals are sent from the analyze and enhance units 1752 to the switchunit 1756.

The switch unit 1756 is a selector that receives the decoded streamsfrom all the participants in a conference and transfers the selectedstreams to the mixer 1760. The selection is based on the decisions ofthe control unit 1754. Based on received commands from the MCS 1670,which define the connection status of the participants in the conferencethat is assigned to the signal processing unit 1750, and the informationsignal 1753 from the analyze and enhance unit 1752, the control unit1754 controls, via control signals 1757, the switch 1756, and the mixer1760. For example, in a case where a participant's connection status isNormal (N), the analyze and enhance unit 1752 that is associated withthat participant may indicate that the voice signal meets a certaincriteria such as set forth by VAD, (e.g., such as the energy level beingabove a certain value.). Then, the control unit 1753 via switch 1756selects the output of the analyze and enhance unit 1752, which isassigned to the participant, as one of the inputs to the mixer 1760. Themixer 1760 mixes the selected audio signals to form the mixed signal1761, and broadcasts the mixed signal 1761 over the DACI 1740. Someembodiments of the signal processing unit 1750 have the capability ofeliminating the voice of a speaker from the mixed signal that is aimedto the endpoint of that speaker.

The MCS 1670, based on the connection status stored in the CCDB,commands one or more codecs 1720 to grab the mixed output 1728 from theDACI 1740 for listening to the conference. After grabbing the mixedoutput 1728 from the DACI 1740, the encoder 1724 encodes the decodedsignal from the appropriate signal processing unit 1750, and sends thecompressed signal 1717 via the CACI 1650 to the appropriate participant.

The codecs 1720 and the signal processing units 1750 may be implementedby Digital Signal Processors (DSPs). One DSP can include more than oneunit (e.g., more than one codec and/or bridge). In the above example,the codec 1720 handles one participant's audio signal, and the signalprocessing unit 1750 handles one conference.

In accordance with one embodiment of the present invention, the networkinterface 1642 receives the endpoint signal and determines if there is aseparate data channel encoded along with the audio channel, as would bethe case for IP communications and modem communications. If so, thenetwork interface 1642 detects these data channels and provides themover a Common Data Channel Interface (CDCI) 1675 to embedded data unit1678. If the data is provided as LPSP data, e.g., notch or spreadspectrum over IP, ISDN, modem or analog links, this will travelconventionally over the CACI 1650 to the audio unit 1660. Reverseoperations occur for data which is to be transmitted to an endpointeither as LPSP format from the audio unit 1660 or as a separate datachannel from the embedded data unit 1678.

The embedded data unit 1678 includes a series of codecs 2000, each ofwhich includes a decoder 2002 and an encoder 2004. The decoders 2002 andencoders 2004 are each connected to particular channels of the CDCI 1675so that they can detect channels from particular endpoints, similar tothe manner in which the codecs 1720 in the audio unit 1660 detect itfrom individual endpoints. The decoder 2002 provides decoded controllevel information, i.e., high function level information to a controlunit 2006. The two control units provide the higher level controlinformation as appropriate to the encoder 2004. In this manner, thecontrol unit provides the actual processing and operations of thecontrol information as described above and below.

The operation of the bridge without decoding the data may beaccomplished by assigning priority to the data based on the existence ofLPSP data rather than the content of the data. Accordingly, the data isnot decoded since it can be identified as LPSP data without doing so.

In another embodiment, the bridge architecture is utilized to detect anddecode LPSP signals and use them to control operations and toparticipate in a management link with one or more participants to aconference. As described above, the endpoint could request variousoperations of the bridge which would require the bridge to prepare andtransmit appropriate data, not just necessarily to the requestingendpoint but also potentially to all capable endpoints. Examples ofoperations suitable for receipt by all endpoints include performing aroll call, indicating the participants names on entering and leaving,providing a live status on the number of participants, identifying thecurrent talker, displaying conference information to a new joiner,providing Caller ID information about joining parties; providing votingcapabilities and providing vote results, providing a list of availableconferences and accepting a selection; and identifying a noisy endpoint.An advanced feature that the bridge can provide is that it can act as aninstant messaging (IM) server for the participating endpoints.

In yet another embodiment, the bridge architecture shares LPSP dataamong multiple users by separating the LPSP band, notching otherparticipants if appropriate, and incorporating an LPSP source intosignals transmitted to other participants. These activities areaccomplished without decoding the data for its content.

In the case of LPSP data, the analyze and enhance unit 1752 determinesif LPSP data, e.g., notch or spread spectrum, is present. If so, apresence detect indication is provided to control unit 1754. If thecontrol unit 1754 desires to actually determine what the particular datais, then the analyze and enhance unit 1752 provides the decoded LPSPdata to the control unit 1754 as described further below. If the controlunit 2006 of the embedded data unit 1678 determines that data is to beprovided to an endpoint over an LPSP channel, this data is provided fromthe control unit 2006 to the control unit 1754. The control unit 1754will then provide the data to the analyze and enhance unit 1752 whichwill then encode it in the proper format so that it can be then switchedand mixed in conventional fashion. The control unit 1754 provides thepresence or actual LPSP data to the control unit 2006 for its control ofthe data/control operations according to the present invention.

Various operations and functions of the control unit 2006 includedetermining the actual LPSP data and its destination. If the destinationis the bridge itself, then the control unit 2006 provides thisinformation to the MCS 1670 over a control channel 1674. Similarly, ifthe MCS 1670 provides information to the control unit 2006, this isprovided back to the particular and appropriate endpoints 1610 aa-nk.This control information can be similar to that as described above. Inthis manner or if instead it is LPSP data or other data directed to aparticular endpoint, then the control unit 2006 determines that the datais to be transmitted to a particular end unit and appropriately eitherinstructs the codecs 2000 or the control unit 1754 to properly transmitsuch data from the incoming channel to a desired outgoing channel.

Alternatively, if it is not desired to actually have the bridge becontrolled by the particular endpoint but merely to allow transfer ofthe LPSP or data channels to the other endpoints, the control unit 2006would merely instruct the codecs 2000 and control unit 1754 to look forthe actual presence of the particular data streams. If only a singledata stream is present, the control units 1754 and 2006 instruct thecodecs 2000 and the analyze and enhance units 1752 to extract the datastream without decoding it and replicate it to the other desiredendpoints. If multiple data streams are present and full duplexoperation is available, then the codecs 2000 and analyze and enhanceunits 1752 will replicate the data streams to the appropriate endpoints.If multiple data streams were present and this was not a full-duplexoperation, as could be done in the case of LPSP spread spectrum ormultiple data channels in an IP or modem environment, then the controlunit 2006 would properly blank or cut off communications from any devicethat was not the designated master device, so that only the master coulddo communications in a half-duplex format and not have slave endpointscausing data collisions. When the master has completed operations, onlya single slave should respond and its data stream would be provided tothe master. Thus, the control unit 2006 could perform all of the abovedescribed control functions as appropriate with one or multipleendpoints at any given time by appropriately receiving or providing datato the particular endpoints in a separated manner, either by the use ofindividual separately controlled data channels or by properlyinstructing the analyze and enhance unit and control unit 1754 toprovide individual data to the particular endpoints.

In addition, in accordance with one embodiment of the present invention,the bridge can translate a DTMF signal, for instance, into an LPSPsignal. Conversely, the bridge can translate an LPSP signal into a DTMFsignal.

A conventional multipoint bridge turns off all but the loudest talkersto keep the background noise down. In the common variants somewherebetween 1 and 6 talkers or endpoints are turned on at once, depending onthe bridge and its settings. Because LPSP is intentionally created at avery soft level, the data channel is not loud enough to get through aconventional multipoint bridge by itself because the volume is too lowto activate the active talking detection in the bridge. Recognizing thatLPSP is associated with a telephone or speakerphone, with a humansitting there who is probably going to be talking at some point, thereare several techniques that can be used to allow LPSP data to betransferred using the conventional microphone gating techniques.

a. Send LPSP messages continuously. Chances are that the local personwill talk sometime so that their speech will open up the conventionalmultipoint bridge, and the LPSP message will then ride on top of it andget through.

b. Do (a), but with some limitations. Example limitations includesending a one-second LPSP message every five seconds for one minute,then stopping. This works well in cases where the LPSP control task isto set up the channel for a presenter to show their slides becausepeople rarely put up their slides without saying a word.

c. Monitor the outgoing speech level, and only generate an LPSP messagewhen the outgoing speech is loud enough. This allows the generatingsystem to send fewer messages, and to have more confidence that it willget through.

d. If some time has passed and the generating system has notsuccessfully sent an LPSP message, either make it much louder orgenerate a short synthetic noise to force the conventional multipointbridge open so LPSP can get through.

The invention has been explained with reference to exemplaryembodiments. It will be evident to those skilled in the art that variousmodifications may be made thereto without departing from the broaderspirit and scope of the invention. Further, although the invention hasbeen described in the context of its implementation in particularenvironments and for particular applications, those skilled in the artwill recognize that the present invention's usefulness is not limitedthereto and that the invention can be beneficially utilized in anynumber of environments and implementations. The foregoing descriptionand drawings are, accordingly, to be regarded in an illustrative ratherthan a restrictive sense.

1. A conference endpoint for managing participation in a conference callvia a conference bridge, the conference endpoint comprising: an audioprocessing unit; a control module communicably coupled to the audioprocessing unit; and a network interface communicably coupled to thecontrol module; wherein the control module is operable to transmitcontrol data in combination with audio data to the conference bridge;and wherein the control data comprises an instruction that theconference bridge dial a specified phone number.
 2. The conferenceendpoint of claim 1, wherein the control data comprises the specifiedphone number.
 3. The conference endpoint of claim 1, wherein the controldata comprises a name associated with the specified phone number.
 4. Theconference endpoint of claim 1, wherein the network interface sends andreceives data according to a protocol selected from the group consistingof IP, modem data, ISDN, and analog.
 5. The conference endpoint of claim4, wherein the control data is embedded in the audio data and whereinthe control data is substantially humanly inaudible.
 6. The conferenceendpoint of claim 1, wherein the conference endpoint is selected fromthe group consisting of a computer with a microphone and speaker, anaudio communication device without the control module combined with aseparate control module, a speakerphone, an IP phone, and a videoconferencing unit.
 7. The conference endpoint of claim 1, furthercomprising: a video processing unit communicably coupled to the networkinterface.
 8. A conferencing system comprising: a conference endpoint; amultipoint conference bridge; and a communication channel having acommunication protocol coupling the bridge and the conference endpoint;wherein the conference endpoint comprises a control module operable toprovide control data in combination with audio data to the bridge;wherein the control data is operable to instruct the bridge to dial aspecified phone number; and wherein the bridge dials the specified phonenumber.
 9. The conferencing system of claim 8, wherein the communicationprotocol is a protocol selected from the group consisting of IP, modemdata, ISDN, and analog.
 10. The conferencing system of claim 9, whereinthe control data is embedded in the audio data and wherein the controldata is substantially humanly inaudible.
 11. The conferencing system ofclaim 8, wherein the conference endpoint is selected from the groupconsisting of a computer with a microphone and speaker, an audiocommunication device without the control module combined with a separatecontrol module, a speakerphone, an IP phone, and a video conferencingunit.
 12. A method for adding a conferee to a conference, the methodcomprising the steps of: combining an audio signal and a control signal;sending the combined audio and control signal to a multipoint conferencebridge; and instructing the multipoint conference bridge to dial aspecified phone number based on the control signal.
 13. The method ofclaim 12, wherein the combined audio and control signal is sentaccording to a communication protocol selected from the group consistingof IP, modem data, ISDN, and analog.
 14. The method of claim 12, whereinthe control signal is embedded in the audio signal and wherein thecontrol signal is substantially humanly inaudible.
 15. Acomputer-readable medium comprising instructions for adding a confereeto a conference by performing the steps of: combining an audio signaland a control signal; sending the combined audio and control signal to amultipoint conference bridge; and instructing the multipoint conferencebridge to dial a specified phone number based on the control signal. 16.The computer-readable medium of claim 15, wherein the combined audio andcontrol signal is sent according to a communication protocol selectedfrom the group consisting of IP, modem data, ISDN, and analog.
 17. Thecomputer-readable medium of claim 15, wherein the control signal isembedded in the audio signal and wherein the control signal issubstantially humanly inaudible.